"use strict";

// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = "production";
process.env.NODE_ENV = "production";

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on("unhandledRejection", err => {
	throw err;
});

// Ensure environment variables are read.
require("../config/env");

const path = require("path");
const chalk = require("react-dev-utils/chalk");
const fs = require("fs-extra");
const bfj = require("bfj");
const webpack = require("webpack");
const configFactory = require("../config/webpack.config");
const paths = require("../config/paths");
const checkRequiredFiles = require("react-dev-utils/checkRequiredFiles");
const formatWebpackMessages = require("react-dev-utils/formatWebpackMessages");
const printHostingInstructions = require("react-dev-utils/printHostingInstructions");
const FileSizeReporter = require("react-dev-utils/FileSizeReporter");
const printBuildError = require("react-dev-utils/printBuildError");

const measureFileSizesBeforeBuild = FileSizeReporter.measureFileSizesBeforeBuild;
const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild;
const useYarn = fs.existsSync(paths.yarnLockFile);

// These sizes are pretty large. We'll warn for bundles exceeding them.
const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;

const isInteractive = process.stdout.isTTY;

// Warn and crash if required files are missing
if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
	process.exit(1);
}

const argv = process.argv.slice(2);
const writeStatsJson = argv.indexOf("--stats") !== -1;

// Generate configuration
const config = configFactory("production");

// We require that you explicitly set browsers and do not fall back to
// browserslist defaults.
const {checkBrowsers} = require("react-dev-utils/browsersHelper");
checkBrowsers(paths.appPath, isInteractive)
	.then(() => {
		// First, read the current file sizes in build directory.
		// This lets us display how much they changed later.
		return measureFileSizesBeforeBuild(paths.appBuild);
	})
	.then(previousFileSizes => {
		// Remove all content but keep the directory so that
		// if you're in it, you don't end up in Trash
		fs.emptyDirSync(paths.appBuild);
		// Merge with the public folder
		copyPublicFolder();
		// Start the webpack build
		return build(previousFileSizes);
	})
	.then(
		({stats, previousFileSizes, warnings}) => {
			if (warnings.length) {
				console.log(chalk.yellow("Compiled with warnings.\n"));
				console.log(warnings.join("\n\n"));
				console.log("\nSearch for the " + chalk.underline(chalk.yellow("keywords")) + " to learn more about each warning.");
				console.log("To ignore, add " + chalk.cyan("// eslint-disable-next-line") + " to the line before.\n");
			} else {
				console.log(chalk.green("Compiled successfully.\n"));
			}

			console.log("File sizes after gzip:\n");
			printFileSizesAfterBuild(stats, previousFileSizes, paths.appBuild, WARN_AFTER_BUNDLE_GZIP_SIZE, WARN_AFTER_CHUNK_GZIP_SIZE);
			console.log();

			const appPackage = require(paths.appPackageJson);
			const publicUrl = paths.publicUrlOrPath;
			const publicPath = config.output.publicPath;
			const buildFolder = path.relative(process.cwd(), paths.appBuild);
			printHostingInstructions(appPackage, publicUrl, publicPath, buildFolder, useYarn);
		},
		err => {
			const tscCompileOnError = process.env.TSC_COMPILE_ON_ERROR === "true";
			if (tscCompileOnError) {
				console.log(
					chalk.yellow("Compiled with the following type errors (you may want to check these before deploying your app):\n")
				);
				printBuildError(err);
			} else {
				console.log(chalk.red("Failed to compile.\n"));
				printBuildError(err);
				process.exit(1);
			}
		}
	)
	.catch(err => {
		if (err && err.message) {
			console.log(err.message);
		}
		process.exit(1);
	});

// Create the production build and print the deployment instructions.
function build(previousFileSizes) {
	console.log("Creating an optimized production build...");

	const compiler = webpack(config);
	return new Promise((resolve, reject) => {
		compiler.run((err, stats) => {
			let messages;
			if (err) {
				if (!err.message) {
					return reject(err);
				}

				let errMessage = err.message;

				// Add additional information for postcss errors
				if (Object.prototype.hasOwnProperty.call(err, "postcssNode")) {
					errMessage += "\nCompileError: Begins at CSS selector " + err["postcssNode"].selector;
				}

				messages = formatWebpackMessages({
					errors: [errMessage],
					warnings: []
				});
			} else {
				messages = formatWebpackMessages(stats.toJson({all: false, warnings: true, errors: true}));
			}
			if (messages.errors.length) {
				// Only keep the first error. Others are often indicative
				// of the same problem, but confuse the reader with noise.
				if (messages.errors.length > 1) {
					messages.errors.length = 1;
				}
				return reject(new Error(messages.errors.join("\n\n")));
			}
			if (
				process.env.CI &&
				(typeof process.env.CI !== "string" || process.env.CI.toLowerCase() !== "false") &&
				messages.warnings.length
			) {
				// Ignore sourcemap warnings in CI builds. See #8227 for more info.
				const filteredWarnings = messages.warnings.filter(w => !/Failed to parse source map/.test(w));
				if (filteredWarnings.length) {
					console.log(
						chalk.yellow(
							"\nTreating warnings as errors because process.env.CI = true.\n" + "Most CI servers set it automatically.\n"
						)
					);
					return reject(new Error(filteredWarnings.join("\n\n")));
				}
			}

			const resolveArgs = {
				stats,
				previousFileSizes,
				warnings: messages.warnings
			};

			if (writeStatsJson) {
				return bfj
					.write(paths.appBuild + "/bundle-stats.json", stats.toJson())
					.then(() => resolve(resolveArgs))
					.catch(error => reject(new Error(error)));
			}

			return resolve(resolveArgs);
		});
		compiler.hooks.done.tap("BuildTimeLogger", stats => {
			const time = (stats.endTime - stats.startTime) / 1000;
			console.log(`🕒 本次构建耗时：${time.toFixed(2)} 秒`);
		});
	});
}

function copyPublicFolder() {
	fs.copySync(paths.appPublic, paths.appBuild, {
		dereference: true,
		filter: file => file !== paths.appHtml
	});
}
